A vacuum supply gas cylinder having a safety design for releasing a gas under a negative pressure environment, consisting of:
- a cylinder body, comprising an accommodating space for storing the gas and an opening located at one end of the accommodating space;
- a cylinder valve, for closing the opening of the cylinder body and comprising an output/input port and a channel, wherein two ends of the channel respectively communicate with the output/input port and the accommodating space of the cylinder body, and the output/input port is integrated into a valve port adapted to allow the gas to enter to and to release from the cylinder body;
- a pipeline structure, comprising a first pipeline and a second pipeline, wherein the first pipeline comprises a first end connected to the channel and a second end extending into the accommodating space, the second pipeline is connected to the first pipeline, the gas stored in the accommodating space flows toward the first end through the second end of the first pipeline when the gas is released from the accommodating space, and the gas flows toward the second pipeline via the first end of the first pipeline when the gas is supplied to and stored in the vacuum supply gas cylinder;
- a first check valve, wherein the first check valve is a one-way valve and disposed at the first pipeline, a connection of the second pipeline and the first pipeline is located between the first end and the first check valve, and the first check valve has an opening pressure for a gas flow direction from the second end to the first end;
- a positive pressure regulating valve, disposed at the first pipeline and closer to the second end of the first pipeline than the first check valve, wherein the positive pressure regulating valve has an output pressure, the output pressure has a direction same as the gas flow direction from the second end to the first end, can adjust the gas in the accommodating space from high pressure to low pressure, and is set at a predetermined value;
- and
- a second check valve, wherein the second check valve is a one-way valve and disposed at the first pipeline, and the second check valve is in the same direction as the flow direction of the gas input and stored in the second pipeline,
- wherein the output pressure of the positive pressure regulating valve is expressed as P1, and the opening pressure of the first check valve is expressed as P2, wherein when P1<P2, the gas is stored in the accommodating space;
- and the output/input port is adapted to be connected to a negative pressure vacuum device to provide a vacuum degree for releasing the gas, wherein when a negative pressure of the vacuum degree relative to the accommodating space is expressed as P3, the gas is released from the accommodating space when P1+P3>P2.